Excess parison remover

ABSTRACT

Apparatus for use in combination with an extrusion blow mold process for disposing of excess extruded tubular material not utilized within the mold. Such apparatus includes metallic means carried by the mold halves for grasping and cooling the free end of such extruded material, and means for controllably releasing such material at an appropriate location within the cycle of the molding apparatus.

United States Patent Garver Mar. 19, 1974 [5 EXCESS PARISON REMOVER3.078.508 2/1963 Martin 425/010. 208 x 3,488,803 l/l970 Cote 425/305 B[75] Inventor: Edward B. Garver, Merrionette 33l0834 3H9 Simpson e M264/99 X Park, Ill.

[73] Assignee: Continental Can Company, lnc., primary Examine, RiChardLazarus New York Attorney, Agent, or FirmDiller. Brown, Ramik & 221Filed: Feb. 22, 1972 wlght Appl, No.: 228,029

US. Cl. 425/305 B, 425/310, 425/387 B, 425/806, 425/DIG. 212

Int. Cl B29d 23/03 Field of Search 425/310, 311, 314, 806, 425/DlG. 208,DIG. 212, 302 B, 305 B, 387 B; 264/94, 98, 99

References Cited UNITED STATES PATENTS B/l96l Schaich 425/806 X [5 7ABSTRACT 8 Claims, 4 Drawing Figures EXCESS PARISON REMOVER BACKGROUNDOF THE INVENTION This invention relates to an extrusion blow moldingapparatus in which extruded material is continuously delivered to one ormore molds for forming a bottle or other article therein. Moreparticularly. the instant invention is designed to efficiently disposeof excess material which is extruded but not utilized within the molds.

In the conventional extrusion blow molding process, plasticized materialis continuously extruded from an orifice in the shape of a hollow tube.A series of mold halves carried by an appropriate machine are actuatedto sequentially close about segments of such tubing, and expand sameinto the desired configuration. However, the tubing outside the moldsand between the expanded segments represents waste material which mustbe recycled. In the absence of a proper disposal technique. this excessextruded material, in the form of a hot, plasticized tube, often fallsupon the machine or upon formed articles as they are ejected from themolding apparatus. Since such excess material may constitute up to 30%by weight of the extruded material, a substantial recycling problem mayexist.

SUMMARY OF THE INVENTION In order to overcome such problems, the instantinvention preferably includes two metal plates, one of which is attachedto the exterior of each of the mold halves. As the molds close, one ofthe plates forces the excess extruded material into a cutout section onthe other plate. Due to the high thermal conductivity of the plates,heat from the extruded material may be transferred through the platesand the mold to aicooling fluid passing therethrough. This heat transfercauses the material to be solidified and held within the cutout section.Subsequently, a knockout apparatus may be utilized to discharge suchplastic material from the cutout section at an appropriate place in thecycle of the machine whereby recycling may be facilitated.

Accordingly, it is an object of the instant invention to provide meansfor grasping, controlling and disposing of excess extruded material notutilized by the molds in manufacturing an article. Too, it is a furtherobject of the instant invention to facilitate the recycling of suchmaterial whereby it may be conveyed to a grinder, and then back to theextruder without being contaminated.

Finally. it is an object of the instant invention to provide a means forcontrolling excess extruded material in a most economical and feasiblemanner requiring very little maintenance.

DESCRIPTION OF THE DRAWINGS The manner in which the objects of thisinvention are attained will be made clear by a consideration of thefollowing specification and claims when taken in con junction with thedrawings in which:

FIG. 1 is a symbolic illustration of a molding apparatus with which theinstant invention may be utilized;

FIG. 2 is a side elevational view, partially in section of the instantinvention in its association with an expansion mold;

FIG. 3 is a front elevational view of the instant invention on anexpansion mold; and

FIG. 4 is an enlarged side elevational view of FIG. 2.

DETAILED DESCRIPTION The instant invention will find particularapplication in an environment symbolically represented in FIG. 1 as aseries of expansion molds 5 carried by a wheel of the continuous rotarytype. A more detailed description of such a mold apparatus may be foundin US. Pat. No. 2,784,452 issued to Herbert S. Ruekberg and John L.Szajna on Mar. 12, 1957. As depicted, this series of molds 5 are carriedon a wheel (not shown) for rotation in a clockwise manner and areadapted to be opened and closed by simple camming means. When the moldsare in their open position and moving downwardly. plasticized material 6issuing from an extruder (not shown) is delivered in a downwarddirection such that the molds may close about the extruded tube. Thisclosing welds the tubing at each end of the mold such that it can beexpanded by fluid pressure in a conventional, well-known manner to formthe desired configuration. Continued rotational movement permits thearticle to solidify, and is subsequently ejected as the molds open.

The material 7 between the molds represents excess extruded material andis normally held by the molds at the weld lines until the molds open.Such excess material remains in the form of a hot melt extended betweenmolds during rotation of the wheel. However, upon mold opening, theexcess material is unrestrained and may adhere to the molds oralternatively may attach itself to the formed article in the absence ofadequate means to dispose of it. As depicted in FIG. 1, and with theutilization of the instant invention, it is anticipated that the excessextruded material 7 will be carried by the mold around the wheel to bedischarged an appropriate point into a conveyor and transferred back tothe extruder for recycling.

The apparatus for controllably grasping and releasing such excessmaterial and the method of operation can be better understood withreference to FIGS. 2 and 3.

As shown, each mold 5 comprises an upper mold half 10 and a lower moldhalf 12 which may be opened and closed in a manner more specificallyshown in the above identified Ruekberg patent. In FIG. 2, the molds aredepicted in the closed position with the article 13 having been expandedby the conventional blowing process. Clamping means 20 in the form ofblades are carried by the mold halves and are adapted to weld theextruded parison material at each end of the mold as the halves l0 and12 are closed. Clamping of the tube 6 at each end to form the desiredarticle will also cause the excess material 7 to be retained by themolds until they are opened.

To insure that such material is controllably released into a conveyor orother collection means, the instant invention utilizes a parison remover22 to first restrain and then dispose of such material. Removal means 22may take the form of an upper metal plate 24 and a lower metal plate 26,the upper plate having a recess 25 therein. with flanges 28 at each endof such recess. Preferably, these metal plates are attached to the moldsin any conventional manner or alternatively, may form an integralportion of the mold. The lower plate 26 as depicted may take the form ofa semi-circle, having an upwardly disposed flat edge 32 thereon. Thus,as the molds close, the edge 32 on the lower plate 26 will act as acompactor forcing excess material into the cutout 25 of the upper metalplate 24.

As is well known in the art. the molds may be cooled by fluidcirculating therethrough, and due to the high thermal conductivity ofthe molds themselves, as well as the plates 24 and 26, heat may beconducted from the excess material 7 into the mold and the fluid passingtherethrough. Accordingly. the excess material will rapidly rigidifywithin the flanges 28 of the cutout 25 holding and locking the excessmaterial in place so as to be retained by the upper plate after the moldhalves 10 and 12 are opened.

After the molds open, the formed article as well as the excess extrudedmaterial must be disposed of and discharged from the mold and theretaining means 22. Accordingly, a knockout pin 50 passes through a bore52 within the upper mold half 10 and is biased in an outwardly directionby a spring 54. Thus, reciprocation of the pin 50 in a downwarddirection, (after the lower mold has moved away from the upper mold asdepicted in FIG. 1) will discharge the formed article 13 from the uppermold half 10. Similarly, a knockout punch 60 is carried by the uppermold half 10 by a bracket 62 for discharging the excess material 7.Preferably, its lower end is disposed between the clamping blades andthe upper plate 24, and is biased outwardly by a spring 58 interposedbetween the upper surface of the upper mold half 10 and a flange 65 onthe upper portion of the punch. Again, it should be appreciated downwardreciprocable movement of the punch 60 will be effective to discharge theexcess material 7 from the retaining plate 24.

Controlled release of both the formed article 13 and the excess material7, may be effected by a cam mechanism depicted in FIGS. 2 and 3. Thiscam mechanism may comprise a bracket 40 carried by and attached to theupper mold half and having an L-shaped upper flange 41. Passing througha recess or aperture 45 within this flange is a cam means 42 having anupper cam surface 44. Thus, should the cam 42 be urged downwardly afirst distance. the knockout pin will be reciprocated downwardly todispose of the formed article while a further downward reciprocation ofthe cam 42 will cause engagement with the knockout punch 60 so as todischarge the excess extruded material.

Such downward movement may be affected by two cam rollers 66 and 68 ofdifferent radii which are fixed upon the frame 67 supporting the wheelin any conventional manner. Thus, the first roller 66, being of areduced diameter will be affective to reciprocate the cam 42 downwardlysufficient to cause the knockout pin to discharge the container.Subsequent rotational movement of the wheel will cause the cam 42 tocome in contact with the roller 68 having a greater diameter which iseffective to reciprocate the cam into engagement with the punch 60 andto discharge the excess material.

Accordingly, individual conveyers may be appropriately placed below thecams rollers 66 and 68 so as to receive the formed article and theexcess extruded material as they are released from the upper mold half.

As disclosed, it is preferred that the retaining means 22 be formed of athermally conductive substance whereby the excess parison material maybe rapidly rigidified. Additionally, it should be appreciated that thecutout 25 as well as the flanges may take substantially any shape aslong as they can mechanically engage the plastic material upon itssolidification. Alternatively. surfaces which have a higher degree offrictional resistance to movement of such excess material may be equallywell acceptable.

1 claim:

1. A molding apparatus comprising a mold formed in at least two halvesand defining therebetween a mold cavity, said mold being of the typewhich opens and closes and is particularly constructed to receivetherein an extruded plastic material tube and to pinch the tube closedat opposite ends of the cavity leaving at at least one end of saidcavity excess plastic material. first release means for ejecting amolded article from said mold, and second release means carried by saidmold for separately and later ejecting excess plastic material from saidmold.

2. The molding apparatus of claim 1 wherein there are retaining meanscarried by said mold at said cavity one end for clasping and retainingexcess plastic material attached to a selected one of said mold halveswhen said mold opens subsequent to a molding operation therein.

3. The molding apparatus of claim 2 wherein said second release meansare operatively associated with said retaining means for ejecting theplastic material retained thereby.

4. The molding apparatus of claim 2 wherein said retaining meansincludes a plate carried by said one mold half and having a recesstherein for receiving excess plastic material, and a second platecarried by the other mold half for compacting excess plastic materialinto said recess.

5. The molding apparatus of claim 4 wherein said retaining means areformed of a heat conductive material and are in heat conductive contactwith the remainder of said mold for transferring heat from the excessplastic material and to rigidify the same in said notch.

6. The molding apparatus of claim 2 wherein said retaining means areformed of a heat conductive material and are in heat conductive contactwith the remainder of said mold for transferring heat from the excessplastic material and to rigidify the same.

7. The molding apparatus of claim 1 together with single actuator meansfor said first and second release means and multiple control means foractuating said single actuator means in sequence to effect the timedactuation of said single actuator means.

8. The molding apparatus of claim 7 wherein there is a lost motionconnection between said single actuator and said second release means,and said multiple control means is of the type providing fordifferentdegrees of actuation of said single actuator.

1. A molding apparatus comprising a mold formed in at least two halvesand defining therebetween a mold cavity, said mold being of the typewhich opens and closes and is particularly constructed to receivetherein an extruded plastic material tube and to pinch the tube closedat opposite ends of the cavity leaving at at least one end of saidcavity excess plastic material, first release means for ejecting amolded article from said mold, and second release means carried by saidmold for separately and later ejecting excess plastic material from saidmold.
 2. The molding apparatus of claim 1 wherein there are retainingmeans carried by said mold at said cavity one end for clasping andretaining excess plastic material attached to a selected one of saidmold halves when said mold opens subsequent to a moldiNg operationtherein.
 3. The molding apparatus of claim 2 wherein said second releasemeans are operatively associated with said retaining means for ejectingthe plastic material retained thereby.
 4. The molding apparatus of claim2 wherein said retaining means includes a plate carried by said one moldhalf and having a recess therein for receiving excess plastic material,and a second plate carried by the other mold half for compacting excessplastic material into said recess.
 5. The molding apparatus of claim 4wherein said retaining means are formed of a heat conductive materialand are in heat conductive contact with the remainder of said mold fortransferring heat from the excess plastic material and to rigidify thesame in said notch.
 6. The molding apparatus of claim 2 wherein saidretaining means are formed of a heat conductive material and are in heatconductive contact with the remainder of said mold for transferring heatfrom the excess plastic material and to rigidify the same.
 7. Themolding apparatus of claim 1 together with single actuator means forsaid first and second release means and multiple control means foractuating said single actuator means in sequence to effect the timedactuation of said single actuator means.
 8. The molding apparatus ofclaim 7 wherein there is a lost motion connection between said singleactuator and said second release means, and said multiple control meansis of the type providing for different degrees of actuation of saidsingle actuator.